Re: translate pirq to irq

[Andrew Cooper <andrew.cooper3@citrix.com>]

On 11/01/2014 22:59, Igor Kozhukhov wrote:
> Hello All,
>
> I see a comment in physdev.h for 'struct physdev_map_pirq', var 'pirq':
> /* IN - high 16 bits hold segment for MAP_PIRQ_TYPE_MSI_SEG */
>
> i have received 'pirq' from hypervisor > 255.
>
> map_irq.domid = DOMID_SELF;                                                   
> map_irq.type = MAP_PIRQ_TYPE_MSI;                                             
> map_irq.index = -1; /* hypervisor auto allocates vector */                    
> map_irq.pirq = -1;                                                            
> map_irq.bus = busnum;                                                         
> map_irq.devfn = devfn;                                                        
> map_irq.entry_nr = i;                                                         
> map_irq.table_base = 0;                                              
> rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);                     
> irqno = map_irq.pirq;
>
> i have:
> irqno = 279 - it is more APIC_MAX_VECTOR(255)
>
> i have a question: how to correct translate pirq to irq for APIC map table ?
>
> all work well on xen-3.4, but it has another realization in function physdev_map_pirq() then for xen-4.2.

Is this for a PV or HVM guest?  I suspect PV, in which case the irqno
handed back will be the event channel on which the notification will
arrive, and has nothing to do with regular IDT vectors.

~Andrew